Oncolytic viral therapy is effected by administering a virus that accumulates in tumor cells and replicates in the tumor cells. For example, vaccinia is an oncolytic virus that accumulates in wounds and tumors. By virtue of replication in the cells, and optional delivery of therapeutic agents, tumor cells are lysed, and the tumor shrinks and can be eliminated. Vaccinia viruses are typically administered systemically or locally. There still exists a need for improved or alternative methods of administering vaccinia viruses for various therapeutic and diagnostic applications. Accordingly, it is among the objects herein, to provide virus compositions that can be employed for diagnostic and/or therapeutic methods.